JP7457231B2 - bearing - Google Patents

Description

The present invention relates to a bearing having rolling elements between an inner ring and an outer ring.

In recent years, with the progress in the development of electric cars (EV cars) and hybrid cars (HV cars), the number of high-voltage parts installed in one car is increasing. As the number of high-voltage components increases, the electromagnetic interference between the components also increases. For example, when high-frequency noise propagates to electronic devices such as in-vehicle radios, it causes noise and malfunctions. Therefore, there is currently a demand for measures against high frequency noise in automobiles. Among these, the inventors of the present application are considering removing high frequency noise using bearings installed in various parts of automobiles.

Here, as a bearing intended to be energized, for example, a rolling bearing 10 is disclosed in Patent Document 1. This rolling bearing 10 has a magnetic annular ferrite 16 embedded in a cage 14 mainly for the purpose of preventing damage to the rolling elements 13 due to electrolytic corrosion. The annular ferrite 16 increases the impedance of the rolling element 13, thereby alleviating rapid discharge around the rolling element 13 and suppressing alternating current, thereby preventing damage to the rolling element 13 and the like due to electrolytic corrosion. .

Japanese Patent Application Publication No. 2004-360823

When investigating the elimination of high-frequency noise using the above-mentioned bearings, the inventors of the present application attempted to realize a configuration in which high-frequency noise propagating through the shaft would be diverted to the outside via the bearings. However, further ingenuity was needed to efficiently reduce high-frequency noise.

In view of such problems, an object of the present invention is to provide a bearing that can efficiently reduce high frequency noise propagated to the shaft.

In order to solve the above problems, a typical configuration of a bearing according to the present invention is a bearing that includes rolling elements between an inner ring and an outer ring, and includes a ring member formed in an annular shape coaxial with the inner ring and the outer ring. The annular member is made of a magnetic material and is characterized in that the annular member attenuates high frequency noise propagated along the shaft.

According to the above configuration, the annular member is used as a so-called ferrite core, and high frequency noise is efficiently attenuated by providing an inductance component to the shaft, thereby making it possible to prevent electromagnetic interference in electronic equipment. As the magnetic material used for the annular member, for example, ferrite or magnetic rubber can be suitably used.

The annular member may be fixed to a retainer that holds the rolling elements. With this configuration, it is possible to arrange an annular member made of a magnetic material around the axis.

The annular member described above may be fixed to the outer ring. This configuration also makes it possible to arrange the annular member made of a magnetic material around the shaft.

The ring member may be embedded in the inner peripheral surface of the inner ring. This configuration also makes it possible to place a ring member made of a magnetic material around the shaft.

The seal further includes a seal that covers the rolling element from the side between the inner ring and the outer ring, the seal is made of a conductive resin material, and the inductance of the annular member and the capacitance of the seal are used to An LC filter may be configured for high frequency noise propagated to.

According to the above configuration, when the axis is used as a propagation path for high-frequency noise, an LC filter can be formed in which the annular member is likened to an inductor and the circuit passing through the seal is likened to a capacitor. Inductors have a property that the higher the frequency of alternating current, the more difficult it is to pass through it, while capacitors have the property that the higher the frequency of alternating current, the easier it is to pass through it. Therefore, according to the above configuration, it is possible to realize a low-pass filter for high frequency noise propagated along the shaft, and to remove high frequency noise more efficiently.

According to the present invention, it is possible to provide a bearing that can efficiently reduce high frequency noise propagated to the shaft.

1 is a diagram showing an overview of a bearing according to an embodiment of the present invention. FIG. 3 is a circuit diagram illustrating the noise filter function of a bearing. It is a figure which illustrated the bearing of the 1st modification. It is a figure which illustrated the bearing of the 2nd modification.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in these embodiments are merely illustrative to facilitate understanding of the invention, and do not limit the invention unless otherwise specified. In this specification and the drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to omit redundant explanation, and elements not directly related to the present invention are not shown or explained. omitted.

FIG. 1 is a diagram schematically showing a bearing 100 according to an embodiment of the present invention. The bearing 100 is embodied as a single-row deep groove ball bearing with a row of balls 106 and a retainer 108 as rolling elements between an inner ring 102 and an outer ring 104. The bearing 100 is intended to be used, for example, in the internal mechanism of an EV vehicle, and has the function of reducing high-frequency noise propagating from high-voltage parts such as a motor to the shaft 110 by each component described below. noise filter function).

The bearing 100 includes a metal shield 112 on one side and a rubber seal 114 on the other side. The shield 112 and the rubber seal 114 cover the ball 106 from the sides between the inner and outer raceway rings, respectively, and prevent lubricating oil from leaking and foreign matter from entering.

The shield 112 is a metal plate having an annular shape and an L-shaped cross section, and is press-fitted into surface contact with the inner peripheral surface of the outer ring 104 (tight fit). An annular member 116 made of a magnetic material is integrally fixed to the shield 112 as an element for realizing the above-described noise filter function.

The annular member 116 is a member made of a magnetic material arranged around the shaft 110 and coaxial with the inner ring 102 and the outer ring 104 and formed in an annular shape. The annular member 116 is fixed to the inner diameter side of the shield 112 so as to be located between the shield 112 and the side surface of the inner ring 102 . At this time, the annular member 116 does not touch the inner ring 102 and remains fixed to the outer ring 104 via the shield 112. As the magnetic material used for the annular member 116, for example, ferrite, magnetic rubber, or the like can be suitably used.

The annular member 116 plays a role as a so-called ferrite core when considering the shaft 110 supported by the bearing 100 as a conductor. Since the annular member 116 is formed from a magnetic material, it provides an inductance component to an axis passing through the center. Generally, the impedance of an inductor (coil) becomes higher as a current with a higher frequency flows through it, making it more difficult for the current to pass through the inductor (coil). Similarly, the annular member 116 made of a magnetic material attenuates high frequency noise propagated to the shaft 110. Thereby, the bearing 100 prevents high frequency noise from being propagated to the electronic device via the shaft 110, and prevents electromagnetic interference in the electronic device.

In addition to the annular member 116, the bearing 100 also includes a rubber seal 114 that serves the noise filtering function. More specifically, the rubber seal 114 is made of a conductive resin material, and is capable of forming a conductive circuit between the inner ring 102 and the outer ring 104.

The rubber seal 114 is of a contact type and is fitted and fixed in a seal groove 115 of the outer ring 104. The rubber seal 114 is formed by a resin portion 118 made of a conductive resin material and a core bar 120 on the center side for supplementing pressure resistance, strength, and conductivity. A lip portion 122 is formed on the inner ring 102 side of the resin portion, and the rubber seal 114 prevents foreign matter from entering by contacting the inner ring 102 with the lip portion 122. At this time, a thin oil film exists between the lip portion 122 and the inner ring 102, and the rubber seal 114 and the inner ring 102 are insulated and function electrically as a capacitor.

The resin portion 118 of the rubber seal 114 is made of, for example, acrylic rubber containing a conductive filler. With this configuration, not only conductivity but also heat resistance can be ensured. This allows the rubber seal 114 to function effectively even in environments where the temperature tends to be high, such as the internal mechanism of a vehicle.

FIG. 2 is a circuit diagram illustrating the noise filter function of the bearing 100. The bearing 100 can be effectively installed between a shaft (shaft 110) of a differential device and the housing 124 in an EV vehicle or an HV vehicle. The shaft 110 connects the motor side 126, which is the noise source, and the drive shaft side 128 towards the wheels.

An inductance 130 caused by the annular member 116 of the bearing 100 (see FIG. 1) and a capacitance 132 caused by the rubber seal 114 of the bearing 100 are generated in the shaft. That is, when the shaft 110 is used as a propagation path for high-frequency noise, the bearing 100 forms an LC filter in which the annular member 116 is an inductor, and the circuit that goes to the housing 124 via the rubber seal 114 is a capacitor. Generally speaking, an inductor has a property that the higher the frequency of alternating current, the more difficult it is to pass through it, and a capacitor has the property that the higher the frequency of alternating current, the easier it is to pass through it. Therefore, according to the bearing 100, it is possible to realize a low-pass filter for the high frequency noise propagated to the shaft 110, and to remove the high frequency noise more efficiently.

As described above, the bearing 100 according to the present invention is capable of preventing high-frequency noise from being transmitted to electronic equipment via the shaft 110, and thus preventing electromagnetic interference in the electronic equipment. The bearing 100 can be suitably realized as various types of bearings, such as deep groove ball bearings and tapered roller bearings. Regardless of the type of bearing realized, the noise filtering function of the annular member 116 and rubber seal 114 makes it possible to suitably reduce high-frequency noise originating from the installation target.

Note that various resin materials other than conductive acrylic rubber can be used as the resin material of the rubber seal 114. For example, nitrile rubber has excellent wear resistance, and fluororubber has high heat resistance and chemical resistance. Silicone rubber also has high heat resistance and cold resistance. Even in these resin materials, by imparting conductivity with a conductive filler, the characteristics of each material are utilized to create a rubber seal 114 with characteristics suitable for the installation target, and a bearing 100 that can reduce high-frequency noise. can be realized.

(Modification)
Modifications of each of the above-mentioned components will be described below. In each of Figures 3 and 4, components that are the same as those already described will be given the same reference numerals and their description will be omitted. In the following description, components with the same names as those already described will have the same functions even if they are given different reference numerals, unless otherwise specified.

FIG. 3 is a diagram illustrating a bearing 150 of a first modification. In the bearing 150, an annular member 152 is integrally fixed to the retainer 108. The annular member 152 is an annular member made of a magnetic material, similar to the annular member 116 in FIG. With the bearing 150 having this configuration as well, it is possible to arrange the annular member 152 made of a magnetic material around the shaft 110 to attenuate high frequency noise propagated to the shaft 110.

Figure 4 is a diagram illustrating a bearing 160 of a second modified example. In the bearing 160, a circular member 162 is embedded in the inner peripheral surface side of the inner ring 102. The circular member 162 is realized by forming a magnetic material into a cylindrical shape. The inner ring 102 has a notch 164 cut out from one side so that the circular member 162 can be inserted in the axial direction. In addition, it is preferable that the circular member 162 has an insulating layer 166 made of an insulating resin film or paint on the inside so that it can be insulated from the shaft 110 when supporting the shaft 110 as part of the inner ring 102. With the bearing 160 of this configuration, the circular member 162 made of a magnetic material is arranged around the shaft 110, and high-frequency noise propagated to the shaft 110 can be attenuated.

The above describes preferred embodiments of the present invention with reference to the attached drawings, but it goes without saying that the present invention is not limited to these examples. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

INDUSTRIAL APPLICATION This invention can be utilized as a bearing provided with a rolling element between an inner ring and an outer ring.

DESCRIPTION OF SYMBOLS 100... Bearing, 102... Inner ring, 104... Outer ring, 106... Ball, 108... Cage, 110... Shaft, 112... Shield, 114... Rubber seal, 116... Annular member, 118... Resin part, 120... Core metal, 122 ...Lip portion, 124...Housing, 126...Motor side, 128...Drive shaft side, 130...Inductance, 132...Capacitance, 150...Bearing of the first modification, 152...Annular member, 160...Bearing of the third modification , 162... Annular member, 164... Notch, 166... Insulating layer

Claims (2)

In bearings with rolling elements between the inner and outer rings,
a cage that holds the rolling elements;
comprising an annular member formed in an annular shape coaxial with the inner ring and the outer ring,
The annular member is made of a magnetic material,
The annular member is provided on a side of the inner ring, and an end of the annular member on the outer ring side is directly or indirectly fixed to the outer ring or the retainer,
The inner ring is formed to be narrower than the outer ring due to the arrangement of the annular member,
A bearing characterized in that high frequency noise propagated to the shaft is attenuated by the annular member. In bearings with rolling elements between the inner and outer rings,
comprising an annular member formed in an annular shape coaxial with the inner ring and the outer ring,
The annular member is made of a magnetic material,
The width of the annular member is narrower than the width of the inner ring, and the annular member is embedded in a notch that is a part of the inner circumferential surface of the inner ring without protruding to the side of the inner ring,
A bearing characterized in that high frequency noise propagated to the shaft is attenuated by the annular member.

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